1. Field of the Invention
The invention relates to a mechanical press
2. Description of the Related Art
In a typical mechanical press of the prior art, an eccentric part 8a of a crankshaft and a slide 3 are connected with a connecting rod 23 as shown in FIG. 10. An adjusting screw rod 24 is provided between connecting rod 23 and slide 3 for adjusting the slide. In this example of prior art, the presence of connecting rod 23 prevents the shortening of the distance between the crankshaft and slide 3, resulting in a taller mechanical press, taller by said distance.
A mechanical press without a connecting rod was proposed by Unexamined Patent Publication S55-48500. Since no connecting rod exists in said example, the height of the machine can be lowered, but it is impossible to provide an adjusting screw rod for slide adjustment making the press very inconvenient to use in press operations.
Another example of prior art is the one disclosed by Unexamined Patent Publication H06-269996. As shown in FIG. 5 of said publication, it comprises: a bush 8 and a sliding piece 9 fitted on an eccentric part 3a of a crankshaft 3; a connecting rod 10 that slidably contains sliding piece 9; and a guide bush 12 provided in a crown for guiding connecting rod 10 in an up and down direction, while connecting rod 10 and a slide 16 are connected via a die height adjusting mechanism 17.
According to said prior art, slide 16 cannot be raised higher than the guide part of connecting rod 10 as connecting rod 10 is guided at the crown as mentioned before. In other words, the machine height cannot be shortened any further.
Another example of prior art is the one disclosed by Unexamined Patent Publication S57-14499. As shown in FIG. 3 of said publication, a guide plate 11 is guided by guide 12. Therefore, a slide 2 cannot go any higher than guide 12, so that the distance between a crankshaft 3 and slide 2 cannot be shortened. Therefore, it is difficult to shorten the height of the machine.
As mentioned in the above, it is difficult to shorten the machine height in all of these prior art machines if there is a connecting rod or something similar to it is used. On the other hand, machines that can be built shorter in heights present inconveniences in press operations.
The invention intends to provide a mechanical press that can be built shorter in height without sacrificing convenience in press operations, while providing merits of stability and longevity.